Shift register too slow for multiplexing?

Hi, I'm trying to figure out working with shift registers. I bought a couple of 74HCT4094's, hooked them up through my breadboard to a small matrix with some LEDs and my Arduino.

Without multiplexing everything works fine, but no matter what circuit I build (changing wires, resistors, transistors, even the Arduino code), when I start to multiplex the LEDS clearly 'flicker' (is that the correct term?).

Is it possible that some shift registers are 'too slow' for multiplexing with Arduino?

Did you make this instructable?

It sounds to me like your shifting isn't happening fast enough, thus making the frame rate low enough to see the flicker. For this flicker to go unseen by our eyes, the refresh rate should be at least 50 Hz (50 times per second), and as Joe mentioned, your 4094 is running at megahertz (millions of times per second!) Chip speed is likely not the issue.

I would think so what is your Arduino clock speed and what is your switching time it my be flickering because the LEDs are turning on and off faster than you can see.

25hz looks like flickering.

Did you check out the free datasheet at the link in my post? Just enter the part number in the serch. The transision times on the clock of the IC 74HCT4094 is 50nS And it my not match the transision time of the Arduino.

The only other thing I can think of is I had a simalar problum with a difrent IC I had to conect the LEDs like I did in my pocket anilyzer at this link.